Introducer for an expandable vascular occlusion device

ABSTRACT

An introducer for introducing an expandable implantable device into a catheter includes an outer tube and an inner core which slides in the outer tube. A first end of the core has a tubular configuration with a slit which allows it to expand radially to grip an end of the device. The first end of the core holding the device is pulled into a first end of the outer tube which further tightens the grip on the device. The second end of the core, which extends beyond the second end of the outer tube, may have a handle attached or be bent to prevent the core from moving and releasing the device. The core preferably has a metal wire inside of it. The device remains in its relaxed condition attached to the introducer at the first end of the outer tube and mostly outside of it until use. The outer tube may have a rigid transparent cup-shaped shield member attached at its first end and extending beyond it to protect the device and allow the device to be viewed on the introducer. To use the introducer and the device, the core is slid relative to the outer tube which pulls the device inside the outer tube and into its stretched condition. As the first end of the inner core exits the second end of the outer tube, the end of the device is released and remains mostly inside of the outer tube in its stretched condition. An end of the outer tube is then inserted into a catheter and a pushrod used to push the device from the introducer into the catheter.

CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY

This application is a continuation in part of U.S. patent applicationSer. No. 08/927,535 filed Sep. 12, 1997, U.S. Pat. No. 5,895,410.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX, IF ANY

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, generally to medical devices. Moreparticularly, the invention relates to expandable implantable devices,particularly vaso-occlusion devices used in radiology and embolotherapy.Specifically the invention relates to devices and methods for installingvaso-occlusion devices.

2. Background Information

In embolotherapy, it is often desirable to occlude blood flow in asection of vasculature for purposes such as controlling internalbleeding, stopping blood supply to tumors, and relieving vessel-wallpressure in a region of a vessel aneurysm. Several devices and methodshave been developed for such purposes, many of which are described inU.S. Pat. No. 4,994,069. Each has significant drawbacks, but the helicalwire coils seem to have found the most favor. One difficulty withhelical wire coils is in pushing, and, if necessary, pulling themthrough the catheter. The wire coil is dimensioned to engage the wallsof a blood vessel and can be relatively stiff and difficult to advancethrough a catheter, especially if the blood vessel has a tortuous path.U.S. Pat. Nos. 5, 226,911 and 5,250,071 describe mechanical devices thatattach and detach to the coils to provide more positive pushing, pullingand positioning capability, but they are relatively complex.

The device of U.S. Pat. No. 4,994,069 (the '069 patent) overcomes manyof the problems with wire coils. It provides a smaller coiled wire thatwhen tensioned has a linear configuration allowing it to be advancedthrough a catheter to the desired site. When the wire exits thecatheter, it relaxes and takes a random convoluted shape to form aspace-filling mass lodged in the vessel at the site of release. However,because the final shape of the relaxed coil in the blood vessel israndom, the precise location and specific length the device occupies inthe vessel cannot be guaranteed. Straightening the long coiled wire andinserting it into a catheter can also be problematic.

A device which overcomes the problems associated with the device of the'069 patent is described in a pending U.S. patent application, Ser. No.08/608,110, titled Self-Expanding Vascular Occlusion Device, filed onFeb. 28, 1996. The above application is hereby incorporated byreference.

The present invention provides a device and method of loading anexpandable vascular occlusion device of the Ser. No. 08/608,110application into a catheter for insertion into vasculature of a patient.A device and method of the present invention may also be useful to loadother expandable devices into catheters, including the device of the'069 patent and other wire coils.

Expandable implantable devices which could benefit from the presentinvention include any device which has a stretched conditioncharacterized by an elongated shape of smaller diameter and a relaxedcondition characterized by a shorter shape of larger diameter. In thepast, such expandable devices have been stored in their stretchedcondition inside a tube. The device may experience creep during longterm storage in that condition. Such creep may prevent the device fromfully returning to the intended shape in its relaxed condition. This isespecially a problem with devices using plastic material in theirspringy components. Another potential problem with devices stored in atubes is that such storage prevents a physician or anyone else fromexamining the device before it is installed. The storage tube may have alabel with a picture or illustration of the device and a description.There is always a potential for mislabeling the tube, or even for thedevice to be missing from the tube.

An introducer of the present invention allows an expandable implantabledevice to be attached to the tip of the introducer, but the deviceremains in its relaxed condition outside of the introducer. The deviceis not subject to creep during long term storage in this condition, andthe device can be examined to verify the device is appropriate for theintended use before the package containing the device and introducer isopened.

It is an object of the present invention to provide an introducer foruse with an expandable implantable device which holds the device in itsrelaxed condition outside of the introducer.

It is another object of the present invention to provide an introducerfor use with an expandable implantable device which pulls the deviceinto the introducer, moving it into its stretched condition as it doesso.

It is yet another object of the invention to provide an introducer foruse with an expandable implantable device which places the device in itsstretched condition in a predetermined position within the introducer.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an apparatus for introducing a selfexpanding vascular occlusion device or other expandable implantabledevice into a catheter. The invention comprises an outer tube and aninner core sliding within an axial bore in the outer tube. The innercore has a distal end, a distal end portion of tubular configurationwith at least one slot which allows the distal end portion to expandradially to receive and grip an end of an implantable device. The innercore has a proximal end extending beyond the proximal end of the outertube when the distal end of the inner core is aligned with the distalend of the outer tube. The expandable implantable device is held by anintroducer of the present invention in its relaxed condition outside ofthe outer tube prior to use.

An expandable implantable device is attached to an introducer of thepresent invention by first positioning the inner core relative to theouter tube so that the distal end portion of the inner core extendsbeyond the distal end of the outer tube. An end of an expandableimplantable device is inserted into the distal end of the inner core sothat the distal end portion expands radially and grips the end of thedevice. The inner core is slid proximally to move the distal end portiongripping the end of the implantable device into the outer tube's axialbore at its distal end, thereby tightening the grip of the distal endportion on the end of the implantable device. Proximal motion of innercore is stopped when the distal end of the inner core is aligned withthe distal end of said outer tube. A handle may then be attached to theproximal end of the inner core, the handle being constructed andarranged to interact with the proximal end of the outer tube so as toprevent said inner core from sliding distally and releasing the end ofthe implantable device.

To use an introducer of the present invention, the inner core is slidproximally which pulls the expandable device into the axial bore of theouter tube tightening the inner core's grip on the end of the device andmoving the device to its stretched condition as it does so. Continuedsliding of the inner core proximally moves the implantable device alongthe axial bore of the outer tube. When the distal end of the inner coreexits the proximal end of the outer tube, the distal end portionreleases the implantable device such that most of the device remainsdisposed inside the outer tube in its stretched condition. The distalend of the outer tube is then installed in an opening in a catheter anda pushrod is used to push the device in its stretched condition distallyback along the axial bore of the outer tube and into the catheter.

In one embodiment, the introducer further includes a hub having an axialbore which receives the outer tube. The hub has a larger diameterportion to facilitate manual gripping. The proximal end of the hubaligns with the proximal end of the inner tube.

In another embodiment a similar hub is used. This hub extends proximallybeyond the proximal end of said outer tube, and a sleeve is mounted inthe axial bore of the hub at the proximal end of the hub. The sleeve hasan axial bore with a diameter matching that of the outer tube. Thedistal end of the sleeve is disposed within the axial bore of the huband spaced a distance from the proximal end of the outer tube. This gapbetween the sleeve and the outer tube is sufficiently large to allow thedistal portion of said inner core to release the implantable device asthe distal end of the inner core exits the proximal end of the outertube.

In another embodiment the outer tube has a stepped inner bore with alarger diameter portion at the proximal end, a smaller diameter portionat the distal end, and a shoulder where the two portions meet. Aslidable sleeve is selectively positionable along the proximal portionof the axial bore such that the distal end of the sleeve is spaced adistance from the shoulder or the distal end of said sleeve abuts theshoulder. The slidable sleeve has an axial bore the same diameter as thedistal portion of the axial bore of the outer tube. When the sleeve isspaced a distance from the shoulder, the implantable device is releasedfrom the inner core when the distal end of the inner core passes theshoulder. After the inner core is removed, the sleeve can be sliddistally so that the distal end of the sleeve butts against the shoulderthereby closing the gap along the bore. This facilitates use of a pushrod having a flexible tip which may miss the implantable device orbuckle while trying to push the device back through the outer tube.

In another similar embodiment a slidable sleeve is spring loaded to keepthe gap closed until the distal end portion of the inner core holdingthe end of the implantable device pushed it open. To facilitate this,the axial bore of the sliding sleeve has a slightly smaller diameterthan that of the distal portion of the outer tube, but the diameter isstill large enough to allow the inner core to slide smoothly in it.After the implantable device is released from the inner core, the distalend portion of the inner core contracts and slides through the bore ofthe sleeve and the springs then push the sleeve distally until the gapis again closed.

All of these embodiments may have a handle attached to the proximal endof the inner core after the implantable device is attached to facilitatemanual grasping of the inner core and to prevent said inner core fromsliding distally and releasing the end of the implantable device.

The features, benefits and objects of this invention will become clearto those skilled in the art by reference to the following description,claims and drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is an isometric view of one embodiment of the introducer of thepresent invention as used with a self expanding vascular occlusiondevice.

FIG. 2 is a partially exploded cross sectional view taken along the line2--2 of FIG. 1.

FIG. 3 is an exploded view of the delivery portion of the deliveryportion 32 of the embodiment of FIG. 1.

FIG. 4 is a partially exploded view of the embodiment of FIG. 1 as seenduring assembly.

FIG. 5 is an enlarged view of the area indicated in FIG. 4.

FIG. 6 is a cross sectional view taken along the line 6--6 of FIG. 1.

FIG. 7 is an isometric view of the embodiment of FIG. 1 as seen duringassembly with a self expanding vascular occlusion device exploded awayfrom the introducer.

FIG. 8 is an isometric view of the embodiment of FIG. 1 as seen duringassembly with a self expanding vascular occlusion device attached fromthe introducer.

FIG. 9 is an enlarged view of the area indicated in FIG. 8.

FIG. 10 is an enlarged view of the area indicated in FIG. 1.

FIG. 11 is a partial cross sectional view along line 11--11 of FIG. 9.

FIG. 12 is a cross sectional view of the distal end of the embodiment ofFIG. 1 as used with a wire coil vascular occlusion device.

FIG. 13 is the view of FIG. 11 with a self expanding vascular occlusiondevice partially retracted into the introducer.

FIG. 14 is an enlarged view of FIG. 6 showing how a self expandingvascular occlusion device is released from the retracting portion as theretracting portion is retracted.

FIG. 15 is the view of FIG. 14 with the retracting portion removed.

FIG. 16 is a cross sectional view of the embodiment of FIG. 1 and apushing device which may be used to push an expandable implantabledevice out of the delivery tube.

FIG. 17 is an enlarged view of the area indicated in FIG. 16.

FIG. 18 is a cross sectional view of the distal tip of the embodimentshown in FIG. 16 with the introduced installed in a catheter and a selfexpanding vascular occlusion device being pushed from the introducerinto the catheter.

FIG. 19 is a cross sectional view of the proximal end of a deliveryportion of a second embodiment of the introducer of the presentinvention with a self expanding vascular occlusion device retracted intoit.

FIG. 20 is a cross sectional view of the proximal end of a deliveryportion of a third embodiment of the introducer of the present inventionwith a self expanding vascular occlusion device retracted into it.

FIG. 21 is a cross sectional view of a fourth embodiment of theintroducer of the present invention with a self expanding vascularocclusion device attached to it. This embodiment uses a slip sleeve.

FIG. 22 is the view of FIG. 21 showing the self expanding vascularocclusion device being retracted into it.

FIG. 23 is the view of FIG. 22 with the retracting portion removedshowing how he slip sleeve closes.

FIG. 24 is a cross sectional view of a fifth embodiment of theintroducer of the present invention with a self expanding vascularocclusion device retracted into it. This embodiment uses a spring loadedsliding sleeve.

FIG. 25 is the view of FIG. 24 after the device has been released.

FIG. 26 is an alternate embodiment of the retractable portion of thedevice wherein the retractable portion has an internal metal rod.

FIG. 27 is a cross sectional partially exploded view of a sixthembodiment of the introducer having a shield on one end.

FIG. 28 is a cross sectional view of a unitarily molded embodiment of aportion of the introducer of FIG. 27.

FIG. 29 is a perspective view of the introducer of FIG. 27 with a selfexpanding vascular occlusion device attached.

FIG. 30 is a cross sectional view of a seventh embodiment of theintroducer with a self expanding vascular occlusion device attached.

DETAILED DESCRIPTION

Referring to FIGS. 1-15, an example of one embodiment of the presentinvention is illustrated and generally indicated by the referencenumeral 30. The introducer 30 is described below first in terms of itsmajor structural elements and then in terms of its secondary structuraland/or functional elements which cooperate to perform the introducingfunction.

Referring to FIGS. 1 and 2, introducer 30 comprises an outer tubulardelivery portion 32 and an inner core portion 34 which slides insidedelivery portion 32. Inner core 34 has a handle 80 attached tofacilitate manual grasping of it. Inner core 34 has distal end portion74 which is tubular and is longitudinally slit to grip an end of anexpandable implantable device 100 and hold it at tip 46 of deliveryportion 32 until device 100 is to be used. At that time inner core 34 ismanually pulled proximally, in the direction indicated by arrow A, whichpulls expandable device 100 into delivery portion 32 collapsing device100 as it does so. As inner core 34 is pulled through delivery portion32, device 100 is pulled proximally inside of delivery portion 32 untildistal end portion 74 of inner core 34 reaches gap 68 in deliveryportion 32 whereat slit distal end portion 74 expands to release device100. Inner core 34 is then removed from delivery portion 32. Device 100is then introduced into a catheter by inserting tip 46 of deliveryportion into a catheter and pushing device 100 back through deliveryportion 32 using an appropriate diameter pushrod.

Referring to FIGS. 2 and 3, outer delivery portion 32 comprises adelivery tube 40, a hub 50, and a sleeve 60. Delivery tube 40 and sleeve60 are mounted in hub 50 so that a gap 68 of length L1 is left betweende livery tube 40 and sleeve 60. Hub 50 has a cylindrical shank 52having, a proximal end 54 and a distal end 56. In this embodiment, shank54 has a larger diameter portion at distal end 56 to facilitate manualgripping as delivery portion 32 and retracting portion 34 are pulledrelative to each other. An axial bore 58 extends all the way through hub50 from proximal end 54 to distal end 56.

Delivery tube 40 has a proximal end portion 42 and a distal end portion44. Proximal end portion 42 is inserted into bore 58 at distal end 56 ofhub 50 until a point 48 on delivery tube 40 aligns with distal end 56 ofhub 50. Delivery tube 40 is then bonded in place with adhesive 92, suchas epoxy. Distal end portion 44 of delivery tube 40 has an exteriortaper 47 to tip 46.

Sleeve 60 is a tubular body having a distal portion 62 and a proximalportion 64. Sleeve 60 has an inner diameter which matches that ofdelivery tube 40. Distal portion 62 of sleeve 60 has an outer diameterwhich also matches that of delivery tube 40. Proximal portion 64 has anouter diameter larger than that of distal portion 62 but smaller thanthe outer diameter of shank 52 of hub 50. Shoulder 66 is formed at thejuncture of distal portion 62 and proximal portion 64. Distal portion 62of sleeve 60 is inserted into bore 58 at proximal end 54 of hub 50 untilshoulder 66 stops against proximal end 54 of hub 50 and sleeve 60 isbonded in place. The lengths of hub 50, proximal end portion 42 ofdelivery tube 40 and distal portion 62 of sleeve 60 are such that a gap68 is left between delivery tube 40 and sleeve 60 when they are properlybonded in bore 58 of hub 50. This gap is important to facilitatereleasing of an expandable device by retracting portion 34 and care mustbe taken that material used to bond delivery tube 40 and sleeve 60 intohub 50 does not flow into gap 68.

Referring to FIGS. 2, 4, and 5, inner core 34 comprises a collet tube 70and handle 80. Collet tube 70 has a proximal end portion 72 and a distalend portion 74. Collet tube 70 is preferably tubular throughout itslength, but it mat be a solid core with only its distal end portionbeing tubular. Distal end portion 74 has a longitudinal slit 76bifurcating it for a length of L2 into portions 75 and 77. Afterdelivery portion 32 has been assembled, proximal end portion 72 ofcollet tube 70 is inserted into tip 46 of delivery tube 40 and slidthrough delivery portion 32 in the direction indicated be arrow B sothat proximal end portion 72 extends well beyond sleeve 60.

Referring to FIGS. 2, 4, and 6, handle 80 has an axial bore 82 ofsufficient diameter to receive collet tube 70. At distal end 89 ofhandle 80, axial bore 82 has a portion 84 of sufficient diameter andlength to receive sleeve 60 with a slight friction fit and allow distalend 89 of handle 80 to butt against proximal end 54 of hub 50. In thisembodiment, portion 84 is larger diameter than the rest of axial bore82, but all of axial bore 82 may have a diameter of portion 84. In thisembodiment, handle 80 has external features such as circumferentialgrooves 86 to facilitate manual gripping of handle 80.

Handle 80 is slipped over proximal end portion 72 of collet tube 70,which extends beyond sleeve 60, and slid along collet tube 70 in thedirection indicated by arrow C so that sleeve 60 engages portion 84 ofaxial bore 82 and distal end 89 of handle 80 butts against proximal end54 of hub 50. Collet tube 70 is then further advanced through deliveryportion 32 in the direction indicated by arrow B so that distal endportion 74 of collet tube 70 is near tip 46 of delivery tube 40 andproximal end portion 72 of collet tube 70 extends beyond proximal end 88of handle 80.

Referring to FIGS. 7, 8, and 9, an expandable implantable device such asa vascular occlusion device 100, described in pending U.S. patentapplication, Ser. No. 08/608,110 is installed in distal end portion 74of collet tube 70. Expandable vascular occlusion device 100 has aplurality of hubs 102 and a plurality of braided wires 104 connectinghubs 102. Braided wires 104 have been heat set so that when device 100is in a relaxed state as shown in FIGS. 7, 8, and 9, device 100resembles two cones with apexes pointing toward each other. Forsimplicity, only an outer contour of device 100 is illustrated. Whenhubs 102 are pulled axially, device 100 stretches into a tubular form ofgreater length and smaller diameter than it has in its relaxed state.

An end hub 102 of device 100 is inserted into distal end portion 74 ofcollet tube 70. The inside diameter of collet tube 70 is smaller thanthe outer diameter of hub 102. In one embodiment, hub 102 has an outerdiameter of 0.030 inches and collet tube 70 has an inner diameter of0.017 inches. The larger diameter of hub 102 forces slot 76 to open ashub 102 is advanced into distal end portion 74 thereby separatingportions 75 and 77 of collet tube 70. Preferably, nearly the entirelength of hub 102 is inserted into distal end portion 74. Length L2 ofslot 76 should be long enough that hub 102 can be easily inserted, butshort enough that portions 75 and 77 resist being separated and therebygrip hub 102. In this embodiment, slot length L2 is about twice thelength of hub 102.

Referring to FIGS. 1, 10 and 11, with device 100 held by portions 75 and77 of collet tube 70, collet tube 70 is than further advanced throughdelivery portion 32 so that portions 75 and 77 are withdrawn intodelivery tube 40 and end 79 of collet tube 70 is approximately flushwith tip 46 of delivery tube 40. Portions 75 and 77 should not bewithdrawn so much into delivery tube 40 that wires 104 are deformed bytip 46 of delivery tube 40.

Referring to FIGS. 1 and 6, with device 100 properly positioned relativeto delivery tube 40, adhesive 90 such as epoxy is applied to proximalend 88 of handle 80 and collet tube 70 at proximal end 88 of handle 80to secure collet tube 70 to handle 80. After adhesive 90 has solidified,excess collet tube 70 extending beyond adhesive 90 is trimmed offIntroducer 30 with expandable implantable device 100 attached is nowcompleted and ready to be stored. It may be sterilized and stored in asealed transparent bag or tube.

Referring to FIG. 12, other expandable implantable devices such asvascular occlusion coil 110 may be used with introducer 30. An end 112of coil 110 is inserted between portions 75 and 77 of collet tube 70 andwithdrawn into tip 46 of delivery tube 40 in a similar manner as was hub102 of device 100.

An introducer of the present invention may be suitable for use with anyother expandable implantable device, such as a stent, which has astretched condition characterized by an elongated shape of smallerdiameter and a relaxed condition characterized by a shorter shape oflarger diameter. An implantable device remains attached to theintroducer but the device remains in its relaxed condition outside ofthe introducer. The device is not subject to creep during long termstorage in this condition, and the device can be examined to verify thedevice is appropriate for the intended use before the package containingthe device and introducer is opened.

Referring to FIGS. 1, 11 and 13, when an implantable device such asdevice 100, is to be introduce into a catheter, handle 80 is manuallypulled away from hub 50 in the direction indicated be arrow A, whichmoves collet tube 70 in the direction indicated by arrow D and pullsexpandable device 100 into delivery tube 40 collapsing device 100 as itdoes so.

Referring to FIG. 11, distal end portion 44 of delivery tube 40 has aninner wall portion 41 of reduced diameter extending from tip 46 totransition region 45 between inner wall portion 41 and inner wall 43.The diameter of inner wall portion 41 is reduced from the diameter ofthe inner wall 43 along the rest of delivery tube 40 to compensate forthe reduced radial stiffness due to the tapering wall thickness indistal end portion 44. As hub 102 and portions 75 and 77 of collet tube70 are drawn into distal end portion 44 of delivery tube 40, distal endportion 44 compresses portions 75 and 77 of collet tube 70 firmlyagainst hub 120 like a collet. Portions 75 and 77 exert an outward forceon distal portion 44. Because the wall thickness of distal portion 44 isthinner than the rest of delivery tube 40, distal portion 44 will deformoutward more than the rest of delivery tube 40. If inner wall portion 41had a diameter the same as inner wall 43 of the rest of delivery tube40, the greater outward expansion near tip 46 may reduce the holdingforce of portions 75 and 77 against hub 102 enough that hub 102 wouldpull out of collet tube 70 as collet tube 70 is further retracted andfrictional resistance of wires 104 against tip 46 is encountered. Suchan occurrence would render introducer 30 useless. The reduced diameterof inner wall portion 41 compensates for that by forcing distal endportion 44 to elastically expand more than the rest of delivery tube 40as portions 75 and 77, and hub 102 pass. A greater compression force isexerted on portions 75 and 77 than if the diameter of inner wall portion41 had not been reduced. The compression load of the distal end portion44 with a thinner wall of lesser inner diameter expanding farther isthen similar to that of the rest of delivery tube 40 with a thicker wallof greater inner diameter expanding less. That maintains enough holdingforce on hub 102 so it does not pull out of collet tube 70 as device 100is pulled into delivery tube 40.

In one embodiment, the inner diameter of reduced diameter portion 41 is0.040 inches and the inner diameter of the rest of delivery tube 40 is0.043 inches. The corresponding outer and inner diameters of collet tube70 are 0.031 and 0.014 inches respectively. The outer diameter of hub102 used with tubes of those dimensions is 0.030 inches, resulting in a0.004 inch diametric compression.

Referring to FIG. 13, as device 100 is pulled into distal end portion 44of delivery tube 40, braided wires 104 encounter tip 46 which forceswires 104 to collapse as device 100 is stretched and pulled. The half ofdevice 100 inside delivery tube 40 has been stretched into a tubularshape tube with braided wires 104 oriented more as illustrated. Braidedwires 104 bulge out against delivery tube 40 as much as allowed by thediameters of inner wall portions 41 and 43. In a similar fashion, theremaining portion of device 100 is pulled into distal end portion 44 ofdelivery tube 40.

Referring to FIG. 14, collet tube 70 and device 100 is retracted in adirection indicated by arrow E along delivery tube 40 until portions 75and 77 of collet tube 70 reach gap 68 between delivery tube 40 andsleeve 60 in hub 50. As end 79 of collet tube emerges from delivery tube40, portions 75 and 77 are no longer radially constrained by inner wall43 of delivery tube 40 and they spring open releasing hub 102. Collettube 70 is then pulled the remaining distance out through sleeve 60. Gap68 has a length sufficient to allow portions 75 and 77 to release hub102. That length is preferably at least as long as the length L2 of slot76 between portions 75 and 77.

Referring to FIGS. 15, device 100 is now positioned in delivery tube 40such that end hub 102 is partially protruding into gap 68. Frictionbetween wires 104 and inner wall 43 keep device 100 in that position.

Referring to FIGS. 16, 17 and 18, to introduce device 100 into acatheter 120, external taper 47 of delivery tube 40 is inserted into anend 122 of catheter 120, which frictionally holds delivery tube 40 inplace. Catheter 120 preferably has an inner diameter close to the innerdiameter of delivery tube 40, however, it is not necessary to have aclose diameter match. A catheter could be, for example, 0.007 incheslarger. A pushrod 95 having an outer diameter similar to that of collettube 70 is inserted into sleeve 60 and advanced distally in thedirection indicated by arrow F until tip 97 contacts hub 102. Pushrod 95may optionally have a handle 96 attached which is similar to handle 80on collet tube 70. Pushrod 95 is then further advanced to push device100 distally inside of delivery tube 40, out tip 46 of delivery tube 40and into catheter 120. Delivery tube 40 may then optionally be removedfrom catheter 120 for further advancing of device 100 through catheter120 with another pushrod or appropriately sized guidewire.

Referring to FIG. 15, sleeve 60 helps align a pushrod so it makes propercontact with hub 102 of device 100 when device 100 is to be pushed outof delivery tube 40. however sleeve 60 and even hub 50 are not necessaryfor an introducer of the present invention to function properly.

Referring to FIG. 19, one alternate embodiment is to use only a deliverytube 140 without a sleeve or hub. When a collet tube is retracted outproximal end 142 of delivery tube 140, hub 120 will be released leavinga portion of hub 120 protruding from proximal end 142. Device 100 can bepushed back into delivery tube 140 a little by pinching hub 120 betweena person's thumb and forefinger and pushing it into delivery tube 140resulting in hub 120 being approximately flush with proximal end 142 ofdelivery tube 140. A pushrod can then be applied to hub 120 and used toadvance device in tube 140. While construction of this embodiment issimpler, the small outer diameter of delivery tube 140 may make it moredifficult to hold when retracting a collet tube or inserting and pushinga pushrod.

Referring to FIG. 20, another alternate embodiment shown works the sameway as the embodiment of FIG. 15, but hub 250 attached to tube 240provides a better grip on delivery tube 240 when retracting a collettube or inserting and pushing a pushrod. Proximal end 254 of hub 25 ispreferably flush with proximal end 242 of delivery tube 240.

Referring to FIGS. 21, 22 and 23, another embodiment of an introducer ofthe present invention is shown in longitudinal cross section. Introducer330 has a delivery tube 340 which may be shorter than in previousembodiments. Delivery tube 340 has an axial bore with a distal portion341 having the same diameter as the inner wall 43 of most of thedelivery tube 40 of previous embodiment, and a proximal portion 343having a diameter of axial bore 58 of hub 50 of a previous embodiment. Ashoulder 345 is formed at the junction of portion 341 and 343. Axialbore proximal portion 343 receives slip sleeve 360. Delivery tube has aflange 342 at its proximal end and an external taper 347 at its distalend terminating in tip 346. Delivery tube 340 preferably may have agreater wall thickness than delivery tube 40 of previous embodiments andexternal taper 347 may be steeper than external taper 47 of previousembodiments. In that case it is not necessary that axial bore distalportion 341 have a reduced diameter corresponding to external taper 347.

Slip sleeve 360 has a flange 364 at its proximal end and a shank 362extending distally from flange 364 which fits inside axial bore proximalportion 343 of delivery tube 340. Slip sleeve 360 is positioned in boreportion 343 to form gap 368 between shoulder 345 and distal end 369 ofslip sleeve. The fit between shank 362 and bore portion 343 should be asnug sliding fit which is tight enough that gap 368 is maintained duringnormal handling of introducer 330 and retracing of collet tube 370, butloose enough that gap 368 can be closed by manually sliding slip sleevedistally by pushing on flange 364. Slip sleeve 360 has an axial bore 366of the same diameter as axial bore distal portion 341 of delivery tube340.

Collet tube 370 has the same dimensions, except for length, as collettube 70 of previous embodiments. It has a proximal end 372 bonded tohandle 380 and a slot 376 at its distal end which bifurcates it intoportions 375 and 377 which hold hub 102 of device 100 at tip 346 ofdelivery tube 340.

Handle 380 has an axial bore 382 which receives proximal end 372 ofcollet tube 370, and a face 384 which abuts flange 364 when device 100is properly held at tip 346. Adhesive 390 affixes handle 380 to collettube 370.

Device 100 is drawn into delivery tube 340 in the same manner as withprevious embodiments. Delivery tube 340 is held while handle 380 ispulled proximally in a direction indicated by arrow G, which pullscollet tube 370 distally and withdraws device 100 into axial bore distalportion 341 of delivery tube 340. As shown in FIG. 22, hub 102 of device100 is released from collet tube 370 when portions 375 and 377 reach gap368. Collet tube 370 is then removed from slip sleeve 360.

Referring to FIG. 23, slip sleeve 360 is then pushed in a directionindicated by arrow H so that shank 362 slides in axial bore proximalportion 343 of delivery tube 340 until distal end 369 of slip sleeve 360abuts shoulder 345 of delivery tube 340 thereby closing gap 368. Flanges342 and 364 are then adjacent each other. Axial bore distal portion 341of delivery tube 340 and axial bore 366 of slip sleeve now form a borehaving one uniform diameter throughout its length. This is important ifa pushrod having a small diameter flexible tip is to be used to pushdevice 100 out of delivery tube 340 and through a catheter. If gap 368were left, the larger inner diameter at gap 368 may allow the flexibletip to miss hub 102 of device 100 or buckle while trying to push hub120, thereby making it impossible to begin pushing device 100 out ofdelivery tube 340. Closing the gap 368 to make a smaller continuousdiameter prevents those occurrences. Introducer 330 has an additionaladvantage of fewer parts and less assembly than the embodiment havingthe separate hub and sleeve which must be assembled. The length of gap368 can also be adjusted if necessary. The relative position of flanges364 and 342 provide a visual indicator of the length of gap 368.

Referring to FIG. 24, another embodiment of an introducer of the presentinvention uses a spring loaded sliding sleeve to close the gap.Introducer 430 has delivery tube 440 similar to delivery tube 340 of theprevious embodiment in that the wall thickness, tip configuration, anddimensions of axial bore distal portion 441, proximal portion 443, andshoulder 445 are the same. Delivery tube 440 has a proximal portion 444and a distal portion 446 joined together at joint 448. Joining may bedone by bonding or by designing joint 446 to snap together. Proximalportion 444 has a flange 442 at its proximal end and an axial bore 447of the same diameter as bore 443.

Slip sleeve 460 has a shank 462 which slides inside bores 443 and 447.Axial bore 466 of slip sleeve 460 is slightly smaller than the diameterof bore 441 of delivery tube 440, but still large enough that collettube 470 will easily slide in it. Tabs 464 and 465 protrude in oppositedirections through longitudinal slots 450 and 452 in proximal portion444 of delivery tube 440. Springs 449 act between flange 442 and tabs464 and 465 to keep slip sleeve 460 disposed distally in slots 450 and452 such that distal end 469 of slip sleeve 460 abuts shoulder 445 ofdelivery tube 440. Collet tube 470 is identical to collet tube 370 ofthe previous embodiment and has a similar handle (not shown) attached.

As collet tube 70 retracts proximally in a direction indicated by arrowG and pulls device 100 into delivery tube 440, portions 475 and 477reach distal end 469 of slip sleeve 460. Friction between portion 475and 477 and 466 slip sleeve 460 caused slip sleeve to slide proximallyin the direction indicated by arrows I. That motion continues untilportions 475 and 477 clear shoulder 445 at which point hub 102 of device100 is released from between portions 475 and 477.

Referring to FIG. 25, as collet tube continues to be retracted in thedirection indicated by arrow G, portions 475 and 477 can come backtogether and slide out of bore 466 as collet tube 470 is removed.Springs 449 then push slip sleeve 460 distally until distal end 469abuts shoulder 445 of delivery tube 440. Device 100 can then be pusheddistally into a catheter. The components of all the above embodimentsare preferably made of a thermoplastic material.

Referring to FIG. 26, another embodiment of the inner core 34 whichapplies to all other embodiments above is inner core 134 having a metalwire 178 disposed inside collet tube 170. Metal wire 178 has a proximalend 177 embedded in adhesive 190 and extends distally along collet tube170 until it terminates at a distal end 179, which is disposedproximally of slit 176 at distal end portion 174 of collet tube 170.Metal wire 178 provides something solid for collet tube 170 to cinchdown against as collet tube elongates and shrinks diametrically undertensile load, thereby reducing recoil or "snapping" of collet tube 170as the inner core 134 is pulled proximally to retract a device. Metalwire 178 has an outer diameter that is preferably about 0.002 inchesless than the inner diameter of collet tube 170 to aid insertion ofmetal wire 178 into collet tube 170.

The embodiment shown in FIG. 26 may be used with implantable devices,such as stents, that have no solid hub for the slit distal end portion174 of collet tube 170 to cinch against. In that case, distal end 179 ofmetal wire 178 may extend into slit 176 of distal end portion 174, orbeyond collet tube 170 to provide a solid core against which a stent canbe clamped by distal end portion 174 of collet tube 170.

Referring to FIGS. 27-29, a sixth, embodiment of the introducer 530 isillustrated.

A delivery tube 540 has a cup-shaped transparent shield member 550affixed to its first end portion 542. The shield member 550 protectsdevice 500 and also facilitates introduction of a pusher or guidewireinto the delivery tube 540 to push the device 500 into a catheter.Collet tube 570 holds a self expanding vascular occlusion device 500,which in this illustration is a ball-shaped device, in a relaxedcondition at first end 546 of delivery tube 540 and within shield member550. Second end portion 574 of collet tube 570 extending beyond secondend 544 of delivery tube 540 is bent into a hook shape 582 to functionas a handle and also to prevent the collet tube 570 from sliding backtoward the shield member 550 and releasing device 500.

Shield member 550 is connected to a first end portion 542 of deliverytube 540. Shield member 550 preferably has a shank portion 552 with aninternal bore which receives first end portion 542 of delivery tube 540.Shank portion 552 is affixed to delivery tube 540 by methods such asgluing or welding, or shank portion 552 may simply have a friction fiton delivery tube 540 and be pressed on it. Shield member 550 could alsobe molded directly onto delivery tube 540. Alternatively, as illustratedin FIG. 28, shield member 550 and delivery tube 540 could be molded as asingle unit. In that case, delivery tube 540 could be an integrallymolded extension of shank portion 552.

Shield member 550 also has cup portion 554 extending from shank portion552. Cup portion 554 has an internal bore 556 large enough to receive aself expanding vascular occlusion device with generous clearance aroundthe device. Bore 556 has a tapered portion 558 extending from end 546 ofdelivery tube 540. The tapered portion 548 guides a pusher or guidewireinserted into bore 556 into end 546 of delivery tube 540.

Delivery tube 540 is similar to delivery tube 40. It is preferably arigid material such as metal or plastic. First end 546 of delivery tube540 opens into bore 556 but does not extend into bore 556. First end 546may have an internal chamfer 548 or radius to facilitate device 500being pulled into delivery tube 540. Delivery tube 540 has a second end544 which may have an external chamfer 549 or radius to facilitate itbeing inserted into a catheter.

Collet tube 570 is similar to the collet tube of FIG. 26 in that, inthis embodiment, it has a metal wire 578 disposed inside of a flexibletube, preferably made of material such as polyethylene. The first endportion 572 of collet tube 570 has a longitudinal slit 576 which allowsfirst end portion 572 to expand radially to receive and grip an end ofdevice 500.

Metal wire 578 is coextensive with second end 577 of collet tube 570,and has an end 579 which terminates a significant distance from firstend portion 572 of collet tube 570 leaving a portion 580 of collet tube570 unreinforced by wire 578. Besides providing something solid forcollet tube 570 to cinch down against, wire 578 also provides stiffnessand memory to second end portion 574 of collet tube 570 so it can beshaped to facilitate grasping.

To install a device 500 in the introducer 530, second end 577 of collettube 570 is inserted into first end 546 of delivery tube 540 and pushedthrough delivery tube 540 until second end portion 574 of collet tube570 extends beyond second end 544 of delivery tube 540 and slit firstend 572 of collet tube 570 extends an inch or so beyond shield member550. An end of device 500 is installed in the slit first end 572 ofcollet tube 570, then second end portion 574 is pulled to slide collettube 102 further through delivery tube 540 and pull device 500 inside ofcup portion 554 of shield member 550. When the end 572 of collet tube570 gripping the device 500 enters the first end 546 of delivery tube540, the grip of end 572 of collet tube 570 on the end of device 500 istightened by compressive loading of end 572 of collet tube 570. Slidingof collet tube 570 is then stopped. Second end portion 574 of collettube 570 is then bent to form a hook 582 at second end 544 of deliverytube 540. The hook 582 serves as a handle for grasping collet tube 570to retract device into delivery tube 540, and also functions to preventthe collet tube 570 from sliding back toward the shield member 550 andreleasing device 500.

As shown in FIG. 29, device 500 is held by introducer 530 in its relaxedcondition outside of the delivery tube 540 prior to use. To use thedevice and the introducer, the hook 582 of the collet tube 570 isgrasped and pulled relative to delivery tube 540, which pulls device 500into delivery tube 540 stretching device 500 to its cylindrical shape asit does so. Continued sliding of the collet tube 570 moves the device500 along the delivery tube 540. When the first end 572 of the collettube 570 exits second end 544 of the delivery tube 540, the collet tube570 releases the device 500 such that most of the device remains in itsstretched condition disposed inside the delivery tube 540 at second end544. Collet tube 570 is discarded and second end 544 of the deliverytube 540 is installed in a catheter. A push rod is then inserted intofirst end 546 of delivery tube 540 and advanced until it contacts device500. The pushrod is used to push the device in its stretched conditioninto the catheter and advance it through the catheter to the desiredsite of deployment. Shield member 550 provides a large diameter graspingmember useful for manually holding the catheter while manipulating thepushrod.

A seventh, and most preferable, embodiment is illustrated in FIG. 30.The delivery tube 640 and shield member 650 of introducer 630 are thesame as delivery tube 540 and shield member 550 in FIG. 27. The collettube 670 is similar to collet tube 70 of FIG. 2 in that it does not havea metal wire inside of it, and it has a handle 680 attached at its end674. If collet tube 670 is sufficiently thick and/or rigid, a metal wireis not needed inside of the collet tube. The introducer 630 is shownassembled and holding a conical shaped covered self expanding vascularocclusion device 600 in its relaxed state. The introducer 630 and device600 are assembled using the same procedure described above forintroducer 530 except that rather than bending the end of the collettube, after sliding of collet tube 670 in delivery tube 640 is stopped,handle 680, which is a sleeve, is slid over collet tube 670 from end 674until it reaches end 644 of delivery tube 670. Collet tube 670 andhandle 680 are then unitized to prevent movement of collet tube 670 inthe opposite direction. Any excess collet tubing extending beyond handle680 is trimmed.

The descriptions above and the accompanying drawings should beinterpreted in the illustrative and not the limited sense. While theinvention has been disclosed in connection with the preferred embodimentor embodiments thereof, it should be understood that there may be otherembodiments which fall within the scope of the invention as defined bythe following claims. Where a claim is expressed as a means or step forperforming a specified function it is intended that such claim beconstrued to cover the corresponding structure, material, or actsdescribed in the specification and equivalents thereof, including bothstructural equivalents and equivalent structures.

What is claimed is:
 1. An introducer for introducing an implantabledevice into a catheter, comprising:(a) a delivery tube having a firstend, a first end portion, a second end and an axial bore which receivesan inner core, the delivery tube further comprising a shield memberconnected to the first end portion of the delivery tube, the shieldmember having a cavity sufficiently large to receive the implantabledevice in a relaxed condition, the cavity communicating with the axialbore of the delivery tube; and (b) the inner core slidably disposedinside the axial bore of the delivery tube, the inner core having afirst end, a first end portion of tubular configuration with at leastone slot which allows the first end portion to expand radially toreceive and grip the end of an implantable device, the inner core havinga second end portion extending beyond the second end of the deliverytube when the first end of the inner core is aligned with the first endof the delivery tube, the inner core sliding through the axial bore ofthe delivery tube to pull an implantable device into the axial bore ofthe delivery tube, the first end portion of the inner core releasing theimplantable device when the first end of the inner core exits the secondend of the delivery tube such that most of the implantable deviceremains disposed inside the delivery tube.
 2. The introducer of claim 1,wherein the delivery tube has a first end portion having an externaltaper.
 3. The introducer of claim 2, wherein the axial bore of thedelivery tube has a second portion of greater diameter and a firstportion of lesser diameter, the first portion being adjacent theexternal taper.
 4. The introducer of claim 1, further comprising ahandle connected to the second end portion of the inner core.
 5. Theintroducer of claim 1, further comprising a wire disposed inside theinner core.
 6. The introducer of claim 5, wherein the wire has a firstend disposed a substantial distance from the at least one slot.
 7. Theintroducer of claim 5, wherein the inner core has a second end, and thewire has a second end disposed at the second end of the inner core. 8.The introducer of claim 5, wherein the inner core is tubular having aninner diameter, and the wire has an outer diameter that is less than theinner diameter of the tubular inner core.
 9. The introducer of claim 1further comprising a hub connected to the delivery tube, the hub havingan axial bore which receives the delivery tube, a first end, a firstportion of larger outer diameter, a second portion of smaller outerdiameter, and a second end; the delivery tube being received in theaxial bore of the hub and the delivery tube extending beyond the firstend of the hub.
 10. The introducer of claim 9, wherein the second end ofthe delivery tube aligns with the second end of the hub.
 11. Theintroducer of claim 10, further comprising a handle connected to thesecond end of the inner core, the handle being disposed adjacent the hubwhen the first end of the inner core is aligned with the first end ofthe delivery tube.
 12. The introducer of claim 9, wherein the second endof the hub extends beyond the second end of the delivery tube.
 13. Theintroducer of claim 11, further comprising a sleeve received by theaxial bore of the hub at the second end of the hub, the sleeve having afirst end, a second end and an axial bore, the axial bore of the sleevereceiving the inner core, the first end of the sleeve being disposedwithin the axial bore of the hub and spaced a distance from the secondend of the delivery tube, the distance being sufficiently long to allowthe first portion of the inner core to release the implantable device asthe first end of the inner core exits the second end of the deliverytube.
 14. The introducer of claim 13, wherein the axial bore of thesleeve and the axial bore of the delivery tube are the same diameter.15. The introducer of claim 13, wherein the second end of the sleeveextends beyond the second end of the hub.
 16. The introducer of claim15, further comprising a handle connected to the second end of the innercore, the handle having a recess which receives the second end of thesleeve, the handle being disposed adjacent the hub when the first end ofthe inner core is aligned with the first end of the delivery tube. 17.The introducer of claim 2, wherein(a) the delivery tube has a flange onthe second end; (b) the axial bore of the delivery tube has a secondportion of greater diameter which receives a sleeve, a first portion oflesser diameter which receives the inner core, and a shoulder where thesecond portion meets the first portion; and further comprising: (c) asleeve slidably engaging the second portion of the axial bore of thedelivery tube, the sleeve having an axial bore which receives the innercore, a first end, a second end, a flange at the second end, a shankextending from the flange and into the second portion of the axial boreof the delivery tube, the sleeve being selectively positionable alongthe second portion of the axial bore of the delivery tube such that (1)the first end of the sleeve is spaced a distance from the shoulder or(2) the first end of the sleeve abuts the shoulder, and when the sleeveis spaced a distance from the shoulder, the implantable device isreleased from the inner core when the first end of the inner core passesthe shoulder.
 18. The introducer of claim 17, wherein the shank of thesleeve has a length such that a distance between the flange on thedelivery tube and the flange on the sleeve is the same as the distancebetween the shoulder in the delivery tube and the first end of thesleeve.
 19. The introducer of claim 18, wherein the axial bore of thesleeve and the first portion of the axial bore of the delivery tube arethe same diameter.
 20. The introducer of claim 18, further comprising ahandle attached to the inner core such that the handle is adjacent theflange on the sleeve when the first end of the inner core is alignedwith the first end of the delivery tube and the sleeve is positioned sothat the first end of the sleeve is spaced from the shoulder in thedelivery tube.
 21. The introducer of claim 17 wherein the sleeve isspring loaded against the flange of the delivery tube to normally keepthe first end of the sleeve butted against the shoulder, but when thefirst end portion of the inner core gripping an end of an implantabledevice reaches the first end of the sleeve, the sleeve moves with thefirst end portion of the inner core until the first end of the innercore passes the shoulder and releases the implantable device, whereuponthe first portion of the inner core contracts radially and the sleeveslides over the first end portion of the inner core until the first endof the sleeve once again butts against the shoulder.
 22. The introducerof claim 1, wherein the shield member is substantially transparent. 23.The introducer of claim 1, further comprising a handle disposed on andattached to the second end portion of the inner core and adjacent thesecond end of the delivery tube when the first end of the inner core isaligned with the first end of the delivery tube.
 24. An introducer forintroducing an implantable device into a catheter, comprising:(a) adelivery tube having a first end, a second end and an axial bore whichreceives an inner core; and (b) an inner core slidably disposed insidethe axial bore of the delivery tube, the inner core having a first end,a first end portion of tubular configuration with at least one slotwhich allows the first end portion to expand radially to receive andgrip the end of an implantable device, the inner core having a secondend portion extending beyond the second end of the delivery tube whenthe first end of the inner core is aligned with the first end of thedelivery tube, the second end portion of the inner core being bent, theinner core sliding through the axial bore of the delivery tube to pullan implantable device into the axial bore of the delivery tube, thefirst end portion of the inner core releasing the implantable devicewhen the first end of the inner core exits the second end of thedelivery tube such that most of the implantable device remains disposedinside the delivery tube.
 25. An introducer for introducing animplantable device into a catheter, comprising:(a) a delivery tubehaving a first end, a second end and an axial bore which receives aninner core; and (b) an inner core slidably disposed inside the axialbore of the delivery tube and a wire disposed inside the inner core, theinner core having a first end, a first end portion of tubularconfiguration with at least one slot which allows the first end portionto expand radially to receive and grip the end of an implantable device,the inner core having a second end and the wire having a second enddisposed at the second end of the inner core, the inner core having asecond end portion extending beyond the second end of the delivery tubewhen the first end of the inner core is aligned with the first end ofthe delivery tube, the second end portion of the inner core being bent,the inner core sliding through the axial bore of the delivery tube topull an implantable device into the axial bore of the delivery tube, thefirst end portion of the inner core releasing the implantable devicewhen the first end of the inner core exits the second end of thedelivery tube such that most of the implantable device remains disposedinside the delivery tube.
 26. The introducer of claim 25, wherein thesecond end portion of the inner core is bent in the shape of a hook. 27.A system for providing an expandable implantable device for introductioninto a catheter comprising:(a) an expandable implantable device havingan end, a relaxed condition of a predetermined diameter and apredetermined length, and a stretched condition of lesser diameter andlonger length; and (b) an introducer for introducing the expandableimplantable device into a catheter, the introducer having:(i) a deliverytube having a first end, a first end portion, a second end and an axialbore which receives an inner core, the delivery tube further comprisinga shield member connected to the first end portion of the delivery tube,the shield member having a cavity sufficiently large to receive theimplantable device in a relaxed condition, the cavity communicating withthe axial bore of the delivery tube; (ii) an inner core slidablydisposed inside the axial bore of the delivery tube, the inner corehaving a first end, a first end portion constructed to receive and gripthe end of the implantable device, the end of the expandable devicedisposed in and gripped by the first end portion of the inner core, thefirst end portion with the end of the implantable device disposed in theaxial bore of the delivery tube at the first end of the delivery tube sothat the implantable device remains in the relaxed condition and most ofthe implantable device is outside of the delivery tube, the inner corebeing slidable to thereby pull the expandable device into and along theaxial bore of the delivery tube in the stretched condition and torelease the implantable device from the first end portion when the firstend of the inner core exits the second end of the delivery tube suchthat most of the implantable device remains in the stretched conditionand disposed inside the delivery tube.
 28. The system of claim 27,wherein the inner core has a second end extending beyond the second endof the delivery tube, and further comprising a handle attached to thesecond end of the inner core, the handle constructed and arranged tointeract with the delivery tube so as to prevent the inner core fromsliding in a direction which would release the end of the implantabledevice.
 29. The system of claim 27, wherein the implantable device is aself expanding vascular occlusion device.
 30. The system of claim 27,wherein the implantable device is a wire coil for occluding vasculature.31. An introducer for introducing an implantable device into a catheter,comprising:(a) a delivery tube having a first end, a first end portionhaving an external taper, a second end and an axial bore which receivesan inner core, the axial bore having a second portion of greaterdiameter and a first portion of lesser diameter, the first portion beingadjacent the external taper; (b) a hub connected to the delivery tube,the hub having an axial bore which receives the delivery tube, a firstend, a first portion of larger outer diameter, a second portion ofsmaller outer diameter, and a second end, the delivery tube beingreceived in the axial bore of the hub and the delivery tube extendingbeyond the first end of the hub, the second end of the hub extendingbeyond the second end of the delivery tube; (c) a sleeve received by theaxial bore of the hub at the second end of the hub, the sleeve having afirst end, a second end and an axial bore, the axial bore of the sleevereceiving an inner core, the first end of the sleeve being disposedwithin the axial bore of the hub and spaced a distance from the secondend of the delivery tube, the second end of the sleeve extending beyondthe second end of the hub; (d) an inner core slidably disposed insidethe axial bore of the delivery tube and the axial bore of the sleeve,the inner core having a first end, a first end portion of tubularconfiguration with at least one slot which allows the first end portionto expand radially to receive and grip an end of an implantable device,the inner core having a second end portion extending beyond the secondend of the delivery tube when the first end of the inner core is alignedwith the first end of the delivery tube, the second end portion of theinner core being bent, the inner core sliding through the axial bore ofthe delivery tube to pull an implantable device into the axial bore ofthe delivery tube, the first end portion of the inner core releasing theimplantable device when the first end of the inner core exits the secondend of the delivery tube such that most of the implantable deviceremains disposed inside the delivery tube; and (e) a handle connected tothe second end of the inner core, the handle having a recess whichreceives the second end of the sleeve, the handle being disposedadjacent the hub when the first end of the inner core is aligned withthe first end of the delivery tube.
 32. An introducer for introducing animplantable device into a catheter, comprising:(a) a delivery tubehaving a first end, a first end portion, a second end and an axial borewhich receives an inner core; (b) a shield member connected to the firstend portion of the delivery tube, the shield member having a cavitysufficiently large to receive the implantable device in a relaxedcondition, the cavity communicating with the axial bore of the deliverytube; (c) a tubular inner core slidably disposed inside the axial boreof the delivery tube, the inner core having a first end, a first endportion with at least one slot which allows the first end portion toexpand radially to receive and grip an end of an implantable device, theinner core having a second end, and a second end portion extendingbeyond the second end of the delivery tube when the first end of theinner core is aligned with the first end of the delivery tube; and (d) ahandle attached to the second end of the inner core, the handleconstructed and arranged to interact with the delivery tube so as toprevent the inner core from sliding in a direction which would releasethe end of the implantable device; the inner core sliding through theaxial bore of the delivery tube to pull the implantable device into theaxial bore of the delivery tube, the first end portion of the inner corereleasing the implantable device when the first end of the inner coreexits the second end of the delivery tube such that most of theimplantable device remains disposed inside the delivery tube.
 33. Amethod of assembling an introducer of claim 1 with an expandableimplantable device comprising the steps of:(a) positioning the innercore relative to the delivery tube so that the first end portion of theinner core extends beyond the first end of the delivery tube; (b)placing the implantable device into the cavity of the shield memberproximate to the first end portion of the inner core; (c) inserting anend of an expandable implantable device into the first end of the innercore so that the first end portion expands radially and grips the end ofthe expandable implantable device; (d) sliding the inner core to movethe first end portion with the end of the implantable device into theaxial bore of the delivery tube at the first end of the delivery tubethereby tightening the grip of the first end portion on the end of theimplantable device; and (e) stopping the sliding of the inner core whenthe first end of the inner core is aligned with the first end of thedelivery tube thereby leaving the implantable device in a relaxedcondition outside of the delivery tube.
 34. A method of using a systemof claim 27 comprising the steps of:(a) sliding the inner core to pullthe expandable device from the cavity of the shield member and into theaxial bore of the delivery tube, the expandable device thereby beingmoved to the stretched condition; (b) continuing to slide the innercore, thereby moving the implantable device along the axial bore of theinner core in the stretched condition, the first end portion of theinner core releasing the implantable device when the first end of theinner core exits the second end of the delivery tube such that most ofthe implantable device remains in the stretched condition and disposedinside the delivery tube; (c) inserting an end of the delivery tube intoan opening in a catheter; and (d) inserting a pushrod into the deliverytube and advancing the pushrod to push the implantable device out thedelivery tube and into the catheter, the implantable device remaining inthe stretched condition.